Filtering out spam with my domain name in recipient address

[bob_oi]

Hello

My email address has my domain in it, ie myname@mydomain.com

Lots of spam makes it into my inbox with recipient address like somerandomstring@mydomain.com

Is there a way to define a rule, with regular expressions or not, that will filter those out? I thought of defining it with *@mydomain.com, but do not know whether it will filter out all my mail or will it know to treat my legit address as an exception.

Thanks

[janusz]

Disable "catch all".

[nudge]

Originally Posted by bob_oi

Hello

My email address has my domain in it, ie myname@mydomain.com

Lots of spam makes it into my inbox with recipient address like somerandomstring@mydomain.com

Is there a way to define a rule, with regular expressions or not, that will filter those out? I thought of defining it with *@mydomain.com, but do not know whether it will filter out all my mail or will it know to treat my legit address as an exception.

Thanks

Another thing you might want to do, if you haven't already is change the SPF flag so that mail not coming from fastmail's servers gets spammed. To do that you change the DNS TXT record for your domain. By default it's:

"v=spf1 include:spf.messagingengine.com ?all"

you have disable that one and add another TXT RR for your domain with:

"v=spf1 include:spf.messagingengine.com -all"

a TTL of an hour is good

[janusz]

Originally Posted by nudge

Another thing you might want to do, if you haven't already is change the SPF flag so that mail not coming from fastmail's servers gets spammed.

So all the legitimate messages not sent from/via Fastmail (I bet very few do come that way) will be marked as spam. Do you really recommend that?

[nudge]

Originally Posted by janusz

So all the legitimate messages not sent from/via Fastmail (I bet very few do come that way) will be marked as spam. Do you really recommend that?

Then the problem is not using smtp.fastmail.com to send your mail. Why wouldn't you ? especially since the latest security changes enable you to use an SMTP only app password for that.

[janusz]

Originally Posted by nudge

Then the problem is not using smtp.fastmail.com to send your mail.

Send whose mail?? My understanding of the OP's post is that mails to somerandomstring@.... are sent from all over the place.

[nudge]

Originally Posted by janusz

Send whose mail?? My understanding of the OP's post is that mails to somerandomstring@.... are sent from all over the place.

Look beyond the @

If the spam arriving in the OP's inbox is coming from a domain he owns that uses Fastmail's DNS service then hopefully it's not coming from Fastmail's servers in which case the SPF -all flag should result in an SPF fail and get them spammed. The login log should also be checked for suspicious SMTP usage to confirm it's not coming from Fastmail in the first place, in that case change passwords.

[n5bb]

Welcome to the EMD Forums, bob_oi! Like januz, I disagree with the comments suggesting that SPF will affect incoming messages sent to your personal domain. SPF only affects the reputation of the message From address, not the recipient address! There is no indication in the post that the spam is coming from any particular domain.

If Fastmail is hosting your domain (so you have an alias entry of *@mydomain.com), then as januz suggests you should disable that alias and add specific aliases for addresses you want to use -- if you are receiving a huge amount of such spam and the spam scores are small. A truly random recipient address at your domain can't be effectively filtered based on the address.

But if you are only getting a few of these a day I wouldn't worry about disabling your wildcard * alias. Just be sure you are using address book whitelisting (keeping common sender addresses in your online Fastmail address book) and look at the spam scores of these messages to see if you can reduce your spam filtering threshold. Use Custom spam filtering and file to spam at a lower threshold so that more of those messages are caught by your spam filter.

If these spam messages have something in common, you may be able to write a rule which will file similar messages to your spam folder. Look at the raw message, especially the X-Spam-source, From, X-Mail-from, and Subject headers. If something is common with most of these type of spam messages, we can help you with creating such a rule.

It also helps if you have you Personal Bayes Spam Filter enabled (see the bottom of the Spam Protection screen for details).

Bill

[bob_oi]

Thanks a lot to everyone!